Pressure distributions on prism-shaped buildings in experimentally simulated downburst

Abstract

Wind loading is one of the most significant factors in civil engineering that influences the structural design considerably. In this paper, a group of manufacturing equipments for downburst simulation based on impinging jet model was developed for investigating the wind loads on structures: including the centrifugal air bellows to generate airflow, a movable platform to realize multiple locations of the building and a freely rotatable turntable to implement alterable building angles. Hundreds of transducers were used to measure the wind action on all surfaces of the building. The pressure coefficients calculated from the observed data were utilized to evaluate the downburst wind load. Pressure distributions on three prism-shaped building models with different placements and angles were investigated to obtain the maximum wind action and mean pressure coefficients. The results showed that the maximum pressure coefficient would reach 1.0 on the top surface if the downburst just broke out over the edifice. Considering that the building was in the developing field of the downburst, the top and the front surfaces would be under high wind pressure and only the back surface would endure wind suction. When the downdraft happens away from the prismatic building, all surfaces, except the front surface, would subject to suction with different degrees. It was also found that the pressure coefficient on the right surface would get its negative peak at first and then go straight up to 0.6 as the angle changed from 0° to 45° and the wind pressure on the front surface would decrease slightly through the whole process. The assertive results provide elemental data for structural wind-resistant design in civil engineering for the downburst-prone areas.